Muscular System Test Review

What is the name of the theory that explains how muscles contract?

Sliding Filament Theory

Rigor Mortis

myosin binds to actin but does not detach, no more ATP is synthesized after death

How long after death does rigor mortis occur?

8-12 hours

How long can rigor mortis last?

more than 2 days

Autolysis

results in the end of rigor mortis; self-digestion of the body’s cells

Muscle Fatigue

inability of the muscles to contract due to lack of oxygen flow to muscles after overuse

Example of muscle fatigue

writer’s cramp

Oxygen Debt

post exercise oxygen uptake, heavy breathing triggered by high levels of lactic acid in muscles; results in more oxygen delivered to muscles to get back to pre-exercise levels

Muscle Atrophy

degeneration of muscles

Muscle Hypertrophy

increase in muscle mass

Muscular Dystrophy

muscles atrophy (decrease in size), no cure, inherited, mutated genes interfere with the production of proteins needed to sustain healthy muscles

Anabolic Steroids

variants of testosterone

Advantages of Anabolic Steroids

increased muscle mass and strength

Disadvantages of Anabolic Steroids

infertility, mood swings, liver damage, acne, shriveled testes

How many attachment points do skeletal muscles have?

at least 2 attachment points: origin and insertion

How do the attachment points work?

insertion moves toward the origin

How do muscles generally work?

pairs or groups

What is it called when muscles work in pairs or groups?

antagonistic muscle action

What is the agonist?

prime mover; produces a specific movement (flexing)

What is the antagonist?

reverses the movement (relaxing, return to resting)

Synergists

move with the agonists to help make movements smooth

Fixators

also called stabilizers, provide support to hold the rest of the body in place when movement occurs

Examples of fixators

muscles along the spine for posture

How are skeletal muscles named?

shape, location, size, direction of fibers, number of origins, location of origin/insertion, action

Shape name

deltoid

Location name

rectus abdominus, temporalis,

Size name

maximus longus

Direction of fibers name

transversus, oblique, rectus

Number of origins name

triceps

Location of origin/insertion name

sternocleidomastoid

Action name

flexor, adductor, extensor

Shin Splints

medial tibial stress syndrome; irritation of anterior tibialis muscle

Torticollis

shortened sternocleidomastoid muscle, causes tilt-”crick” in your neck

Charley Horse

involuntary, painful muscle cramp or spasm, usually caused by dehydration and/or electrolyte imbalance

Define insertion

attachment of the bone that moves when the muscle contracts

Define origin

stable and closer to the center of the body (proximal); fixed attachment point of the bone

What is happening to muscles when they increase in size?

muscle fibers experience tears from exercise; they are repaired when the fibers are fused together

What do you “feel the burn?”

lactic acid buildup